3. Find missing operands 
Manual > PLC Diagnosis > Simatic Graph 7 sequence chain analysis > Description of the operand analysis > 3. Find missing operands 
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In order to find the missing operands in the defined transition the condition tree is processed hierarchically. This can be demonstarted best in the FUP display (see example illustration belo). The following cases are distinguished on finding an operator:
AND
All paths are traced which are not fulfilled at the time of the
evaluation (i.e. red in the illustration).
OR
For each path thefulfilment level, the proportion of fulfilled inputs and the total number of inputs, is calculated. Then only those paths are traced, that have the highest fulfilment level. If thee are several paths with the same fulfilment level, the first one is used.
With this method a possible small but nevertheless  with high probability  meaningful number of operands is found, which can be important for the next step.
In the example illustration this method would only find the operand M102.2, because this is the smallest possible number of operands, which is necessary to change the disturbed transition to undisturbed.

